Antenna



Dec- 21, 1 R. c. VAN CAMP ANTENNA Filed Feb. 21, 1951 INVENTOR. Roscoe 6. Van Camp. BY

AGENTS uni-directional.

United States Patent ANTENNA Roscoe C. Van Camp, Madison, N. J. Application February 21, 1951, Serial No. 212,012

Claims. (Cl. 250-3351) This invention relates to an antenna, and more particularly a television transmitting or receiving antenna. The invention is especially useful in its application to a unidirectional transmitting or receiving apparatus, to which use, however, it is not restricted.

The usual type of television antenna is constructed of elements comprising rods, tubing or the like which are mainly bi-directional. Where maximum signal strength is required, additional complications are necessary involving additional elements, exchange of energy by induction or radiation, adjustment of phase relationship, or the like. Such modifications cause the antenna to be Furthermore, in order to provide a large wave transmission or absorption area it is necessary to make such elements of a size which approaches the impractical from the standpoint of ice and wind load hazards. Finally, in simple television receiving antenna, there is no differential between front and rear absorption areas; and interference from noise, out-of-phase and multi-path signals may be marked.

I have now found it possible to provide an antenna in simple form wherein uni-directional transmission or reception may be effected without complication or undesirable multiplication of elements, wherein a minimum size of elements is required while still maintaining a large wave front area, and wherein a diiferential of absorption area between front and rear of the antenna is very simply realized.

According to the invention, the antenna arms are formed with one face having a number of outward projections, the opposite face being projection-free. Such arms may be constructed of channels nested together, the legs of the channels forming the front of the antenna, that is to say the face toward the transmitted signal. Alternatively, the arms may be formed of a single channel having therein outward projections of other form. Such arms are assembled in an array of conventional form, or as desired.

The invention is shown by way of illustration in the accompanying drawings in which- Fig. l is a front perspective view of an antenna array constructed and arranged according to the invention;

Fig. 2 is an enlarged broken front perspective view of one of the antenna arms shown in Fig. l;

, Fig. 3 is a broken front perspective view of an antenna arm formed of curved channel members; and

Fig. 4 is a broken front perspective view of an antenna arm similarly formed from a single piece of sheet materia In the embodiment of the invention which is illustrated in the Figs. 1 and 2 of the drawings, there is shown an antenna array for transmitting or receiving electromag netic radiation signals comprising a mast 10 and a pair of antenna elements 11 and 12 fixed to the mast and ex tending transversely thereof. The antenna elements 11 and 12 are separated from one another by half-wave spacing, or of a lesser equi-proportional part of a wave length. The over-all length of the elements 11 and 12 is preferably oneehalf wave length. Obviously more than two such elements might be employed to form the Each of the antenna elements 11 and 12 comprises a plate 13 of insulating material fixed to the mast 10 in known or convenient manner, as by U-shaped bolts or straps embracing the mast and having threaded ends 14, 14 extending through the plate 13. Nuts 15, 15 upon the threaded ends 14, 14 serve to tighten the plates 13 2,697,786 Patented Dec. 21, 1954 against the mast 10 and to hold the former in position by frictional engagement. Other Well-known means might, of course, fix the plates 13 and 13 to the mast.

Fixed to each plate 13 of each element, in known or convenient manner (not illustrated) are a pair of spaced antenna arms 16, 16 of novel construction. As here shown the arms 16 are of equal length and are symmetrically disposed with respect to the respective plates 13, being colinear or coaxial and extending oppositely therefrom for equal distances. The plates 13 are fixed to the mast 10 in co-planar position and the antenna arms of the element 11 are parallel to those of the element 12.

Metal connecting members 17 and 18 extend between and in electrical contact with adjacent antenna arms 16 of different plates of insulating material 13. Thus, the member 17 extends between the antenna arms 16 and 16 which project in the same direction from the plates 13 and 13 of the respective elements 11 and 12. Similarly the member 18 extends between the antenna arms which project in the opposite direction from the plates of the respective elements 11 and 12. Conductors 19 and 20 are electrically connected, as at 21 and 22 respectively to the longitudinal centers of metal connecting members 17 and 18 for completing the circuit between the antenna arms and a transmitting or receiving unit (not shown).

The novel antenna arm 16 which is illustrated in Figs. 1 and 2 is integral and is formed with a series of sub stantially equally spaced adjacent projections 23 extending outwardly from one face thereof. The opposite face 24 is projection-free. In this embodiment, the antenna arm is formed of channels 25, 26 and 27 of progressively decreasing cross-section, and of substantially equal longitudinal extent. These channels are nested together, one within the other, with their legs parallel and equally spaced from the legs of the adjacent channel. It is preferred to employ channels of sheet aluminum. The channels are fixed together integrally in electrical connection with their center lines in a single plane, as by rivets 28, by screws, or by welding.

Thus, there is provided an antenna arm having a large wave absorption area on its face toward which the channel legs extend, which may be made in conveniently prac' tical form to avoid excessive ice and wind loads. Furthermore, the differential of absorption area between the face of the antenna from which the projections 23 extend and the opposite face 24 is such as to reduce the effect of noise, out-of-phase effects and multi-path signals emanating from areas to the rear of the antenna. Because of this difierential, the signal-to-noise and signal-to-interference ratios of the novel antenna arm are greatly improved. Finally antenna arms constructed in accordance with the invention have less re-radiation in proportion to wave front area'than do the usual types of antenna. For thisd reason greater signal, intensity is transferred to the loa As is well known, the conventional rod type arm, when used as a component of an antenna ideally matched with its load impedance, transfers approximately one-half of the intercepted signal energy to the load. The other half of the intercepted signal energy is re-radiated from the rod surface. It will accordingly be appreciated that by reducing re-radiation and making possible the transfer of greater signal intensity to the load, the present invention permits the use of antenna'elements of minimum size.

With the type of antenna arm to which the present invention is directed, the waves are virtually trapped between the channel walls. When used as a driven ele ment the re-radiation of the antenna arm is largely confined between the co-planar surfaces of the channels. This bouncing.of the waves from wall to wall is effectually a feed-back of signal energy to the transmission line. Only the outer surfaces of the antenna arm and the front edges of the projections 23 re-radiate the received waves as lost energy.

In the antenna arm 16a which is illustrated in Fig. 3, the channels are semi-cylindrical in cross section, but the construction and arrangement of the channels 25a, 26a and 27a are otherwise the same as that described in connection with the embodiment illustrated in Figs. 1 and 2. In Fig. 4 there is shown a similar antenna arm 16b which is constructed by deforming a single sheet of metal to provide a series of substantially equally-spaced adjacent projections 23b extending outwardly on one face of the antenna. The opposite face 24b of the antenna is projection-free.

It is not intended to limit the use of the novel antenna arm to any particular type of antenna. The antenna may be either driven or parasitic and such antenna arms may be used as dipoles, folded dipoles or other functionaries of driven elements. Furthermore, they may be used as directors or reflectors in parasitic element arrays. In all cases, the present invention makes it possible to employ elements of minimum size.

The forms of the invention here described and illustrated are presented merely to indicate how the invention may be applied. Other forms, embodiments and applications of the invention coming within the proper scope of the appended claims will, of course, suggest themselves to those skilled in the radio and television art.

I claim:

1. An integral antenna arm for transmitting or receiving electromagnetic radiation signals formed of a plurality of longitudinal metal channels nested together with their center lines in a single plane to provide projections extending outwardly from one face of said antenna arm and an opposite projection-free face thereof.

2. An integral antenna arm of electrically conductive material for transmitting or receiving electromagnetic radiation signals comprising a channel and longitudinal outwardly-extending members fixed within said channel, the legs of said channel and said outwardly-extending members forming a plurality of projections extending outwardly on one face of the antenna arm, and the opposite face of the antenna arm being projection-free.

3. An integral antenna arm for transmitting or receiving electromagnetic radiation signals formed of metal channels of graduated size nested together with their center lines in a single plane to provide a series of longitudinal and substantially equally-spaced adjacent projections extending outwardly on one face of said antenna arm and an opposite projection-free face thereof.

4. An antenna arm for transmitting or receiving electromagnetic radiation signals formed of metal channels nested together in electrical contact with one another with their center lines in a single plane and their legs extending outwardly in mutually spaced relation from the front face of the arm.

5. An antenna arm for transmitting or receiving electromagnetic radiation signals formed of metal channels nested together in electrical contact with one another with their center lines in a single plane and the legs of one channel parallel to and equally spaced from the adjacent legs of the next adjacent channel.

6. An antenna arm for transmitting or receiving electromagnetic radiation signals comprising a plurality of metal channels of progressively decreasing cross-section and of substantially equal longitudinal extent, said channels being fixed together one within the other in electrical connection with their legs parallel and equally spaced from the legs of adjacent channels.

7. An antenna array comprising: a mast; and a plurality of plates of insulating material suitably spaced in coplanar positions upon said mast; in combination with a pair of spaced antenna arms fixed to each of said plates and extending oppositely therefrom substantially at right angles to said mast, each of said pair of antenna arms comprising a plurality of metal channels nested together with their center lines in a single plane; metal connecting elements respectively electrically connecting the antenna arms on each side of said mast; and conductors electrically connected to said connecting elements for completing the circuit between said antenna arms and a transmitting or receiving unit.

8. An antenna array comprising: a mast; and a plurality of plates of insulating material suitably spaced in coplanar positions upon said mast; in combination with a pair of spaced antenna arms fixed coaxially to each of said plates and extending oppositely therefrom substantially at right angles to said mast, each of said pair of antenna arms comprising a plurality of metal channels nested together with their center lines in a single plane extending in like direction; metal connecting elements extending substantially parallel to said mast and respectively electrically connecting the antenna arms on each side of said mast; and conductors electrically connected to said connecting elements for completing the circuit between said antenna arms and a sending or receiving unit.

9. An antenna array comprising: a mast; and two plates of insulating material suitably spaced in coplanar positions upon said mast; in combination with a pair of spaced antenna arms fixed coaxially to each of said plates and extending oppositely therefrom parallel to the other pair of antenna arms, each of said pair of antenna arms comprising a plurality of metal channels of progressively decreasing cross section and of substantially equal longitudinal extent, said channels being fixed together one within the other in electrical connection with their legs parallel and equally spaced from the legs of adjacent channels; metal connecting elements extending substantially parallel to said mast and respectively electrically connecting the antenna arms on each side of said mast; and conductors electrically connected to said connecting elements for completing the circuit between said antenna arms and a sending or receiving unit.

10. An antenna array comprising: a mast; a plurality of pairs of antenna arms, the arms of each pair being insulated from one another and extending coaxially and oppositely from said mast; each of said antenna arms comprising a plurality of metal channels nested together with their center lines in a single plane extending in like direction; metal connecting elements respectively electrically connecting the antenna arms on each side of said mast; and conductors electrically connected to said connecting elements for completing the circuit between said antenna arms and a transmitting or receiving unit.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 794,334 Artom July 11, 1905 2,167,709 Cork et a1 Aug. 1, 1939 2,234,122 Heck Mar. 4, 1941 2,297,202 Dallenbach et al. Sept. 29, 1942 2,351,723 Vogel June 20, 1944 2,411,034 Gluyas et al. Nov. 12, 1946 2,481,801 Valach Sept. 13, 1949 2,512,725 Mock June 27, 1950 2,523,531 Flippen Sept. 26, 1950 2,564,675 Crook -2 Aug. 21, 1951 2,608,658 Richards Aug. 26, 1952 FOREIGN PATENTS Number Country Date 115,481 Australia July 19, 1941 

